$6.6 million 'French mistress' tops car auctions

A beautifully restored 1968 Datsun 1600 was sold at an auction for more than $50,000. CNBC's Robert Frank reports on the hottest collectible cars.

A rare, 1937 French Roadster just sold for $6.6 million, proving that rich car collectors are still spending.

Total sales for the collectible-car auctions at the Amelia Island Concours d'Elegance over the weekend topped $66.8 million, a record for the event. That was up 20 percent from last year, and the average sale price topped $400,000, up from $366,787 last year, according to collectible-car insurance firm Hagerty.

The star of the weekend was a 1937 Delahaye 135 Competition Court Torpedo Roadster by Figoni et Falaschi—one of only two surviving examples of the French-built model. RM Auctions sold the car for $6.6 million, topping the high estimate of $6 million.

The car had been owned by the famed collector and car dealer Malcolm Pray, whose wife playfully nicknamed the car "Malcom's French Mistress" because of his fondness for the car. He died last summer.

"No car stops people in their tracks more than a Delahaye," said McKeel Hagerty, CEO of Hagerty.

Source: RM Auctions

A 1937 Delahaye roadster, once owned by classic car collector Malcolm S. Pray Jr., was auctioned for $6.6 million over the weekend at the Amelia Island Concours d'Elegance.

The other top sellers were the typical mix of Ferraris, Porsches and Mercedes-Benzes. Gooding & Co. sold a 1968 Porsche 907 Longtail Coupe for $3.6 million and a 1959 Porsche 718 RSK Spyder for $3.3 million.

But there were some surprises.

A 1958 BMW 507 Roadster was sold by RM for $2.42 million, suggesting that BMWs are starting to make inroads in the collectible car world.

"To restore cars like the Beetle or a Datsun roadster to such a degree of perfection is nothing but an all-in bet that these cars are the collectible gems of the future," Hagerty said. "We look to see these types of cars significantly increase in value over time."